T. Argo, M. Guild, P. Wilson, M. Schroeter, C. Radin, H. Swinney
Sound speed and attenuation in unconsolidated water-saturated glass beads as a function of frequency and porosity
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ABSTRACT.  Sound propagation in water-saturated granular sediments is known to depend on the sediment porosity, but few data in the literature address both the frequency and porosity dependency. To begin to address this deficiency, a fluidized bed technique was used to control the porosity of an artificial sediment composed of 265 micron diameter glass spheres. Time-of-flight measurements and the Fourier phase technique were utilized to determine the sound speed and attenuation for frequencies from 300 kHz to 800 kHz, and porosities from 0.37 to 0.43. A Biot-based model qualitatively describes the porosity dependence, but a transition to a scattering-dominated regime is also observed.